1. Field of Invention
The present invention relates to a novel antimicrobial agent which is effective to inactivate Helicobacter pylori (which is formerly named Campylobacter pylori) and therefore is effective to treat or prevent infections caused by Helicobacter pylori.
2. Description of Prior Art
U.S. Pat. No. 5,013,743 (corresponding to Japanese Patent Provisional Publication No. 3-173817) discloses that pyridine derivatives having a specific formula such as 2-(2-pyridyl)methylsulfinylbenzimidazole are effective to inactivate Campylobacter pylori.
ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, March 1991, p.490-496 describes that lansoprazole and omeprazole have antimicrobial activity against Helicobacter pylori.
Japanese Patent Provisional Publication No. 3-161440 (published on Jul. 11, 1991) discloses that condensed imidazole derivatives having a benzopyran, benzothiopyran, tetrahydroquinoline, or indoline ring are effective to inactivate Campylobacter pylori.
U.S. Pat. No. 5,093,342 discloses that 5-methoxy-2[[(4-methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulfinyl]-1H-benzi midazole is effective for treating infectious diseases caused by Campylobacter pylori.
WO89/03219 (published on Apr. 20, 1989, which corresponds to U.S. Pat. No. 5,196,205) discloses that a bismuth compound is effective to treat infections caused by Campylobacter pylori.
Further, a number of studies concerning relationship between Helicobacter pylori and peptic ulcer or gastritis have been reported. For instance, "Advance of Medical Science (in Japanese)", Vol. 159, No. 10, 1991, pp. 795 is mentioned. There is a report suggesting a relationship between Helicobacter pylori and recurrence of duodenal ulcer.
U.K. published patent application No.2163747 discloses a condensed imidazole derivative which is effective as an anti-ulcer agent, but is silent with respect to antimicrobacterial activity against to Helicobacter pylori.